SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '349f3c6abbff68bad2d6b627c1ee58e6fdb2f237ff47aaa4cf46db4e10b25539' 
  AND token = 'oXYYqwZkO03vzbbflb2Q1I+ePPrTy5m7htYCspnwKn8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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