SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3489553dfff0b1c4cd4840915589b956b6026bae87ef7e092346930c1f46db74' 
  AND token = 'ScULdAcNxYFlaURYXYwgp6k9voqBYUB0jJKAW9WRKFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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