SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '608eb676c10226244b5b07a1d5f99066bfeeb2570b2c5136c69d7c12610a6892' 
  AND token = 'WoNWE9Um9H0mFRQpIBY/VBHZ9CdtIvKF1onvmug+Ho4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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