SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9c0cc34a0ab373f55c88084f91683ff94d084fa1603f187d294240c6972afc9' 
  AND token = 'oPk4AcuQ4JNHwjLBpJXmD7Js7TwwYVXlgyGbHdqc8vo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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