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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e17d0b4df9d5129119fc82b29c72f012a20b57ddc631b5112a8e5381987fe0ac' 
  AND token = 'RPiRxjE3yM9WLFCTQmwtpvQa6rb9tm+ZQGi6O1bfp08=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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