SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a1dabd7912ea3c53b438a0921b8e161836b442cc92b6237abf6d5136bc8aea5' 
  AND token = 'alfSNePz33aNbUhUW1axklK3unYlI2Ce9KQjsp3ZGvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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