SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfef5da41bc847d87dde7ab8afece17af2b1fe52bbc9f941dc552ce36161a629' 
  AND token = 'qikFNjV5UOO3B46DOB8h6V/xLZpQbOKrIcQWu5LEJcE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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