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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef4dfc074213a9fcaeaca9710ac154a0360fc9fc3d8867f02ccb4dbd31ea694c' 
  AND token = 'CClfJlrGtnp2DL+1uOPmPCyTqva+YSt8LsNSsE3B0p8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}