SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1a67a44747ca85fe190335e7e7fc69a555403a495528b40518edb11bb7cc88d' 
  AND token = 'zIK9cvbiVVqyGzTQi4oxV50RYXvvylBEcUKCB812aVM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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