SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8335323922a6afa30608357dc90c3fe4d5a721b2cd7264ab328194cf1ca6b2e' 
  AND token = 'FzB6ugBsp9xWEMDcU8+cBJPgGMFXRjPaqiTVEpBY4zo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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