SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99002ce918f1736d04e4a550b8f52a7c04658a8747108ac849bcf5ccea62b854' 
  AND token = 'wZnsREfrCCFWEvYcL9YexAIDgrXZZbfAgmMVT/J2jZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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