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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ebe536476e1487996907efeaeaba2805f8cad2c15fee26f132c71fe744fa929' 
  AND token = '6kNC4nRQPDW63J6naZwIi6QGAlwLOLzZJidh5cjiTvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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