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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6438e50dc1cfd228621ecc47e4ae9f95e72ac29584b2f6c4e62df2d3f86f3f2' 
  AND token = 'yMhyaGJgZUYtrWoI3UlKXOjerVGL7jGjUNAEsrTMez8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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