SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b696b8a0911c63830e88248c4ed228ced0da34462b3a2e88a9452bc40deceef' 
  AND token = 'WYFISTsJRq/eBA9Rlz0vvTrJUmjI5mHbtrRcXqAm6QE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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