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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6e408c8ee70af52b36423cd19a9ab79ced7186e9516528b456af365a66519a9' 
  AND token = 'bY7xwGslrkHkByD5gchGS3rytBJ2q+XaGS3ezX8hhUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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