SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cc1d0aa57588a8e08b278faa5634311bc31b3424247c104ebd32560553b5718' 
  AND token = 'bqVLBxwL+xtTV2XsBUjasDnqpWrZxGJepX1OaR5RXqI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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