SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc6a8b56b2083f3f3c5366d97120d2b06594d45aa4a6d60882620b66fa6b68f5' 
  AND token = 'kOIQ5oLaUAzVtz0GPbJRLZ6rd5U3ZAGTQvpMI9e21+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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