SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f1d9e815df7af3b176254d57ffd457a6c1e09054e9b42ffad3c29b881496db5' 
  AND token = 'mh42/fgNGSUIKDhqpK0UbczN+T2ibzGqCnygSPzEY0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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