SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be4eb3fd90c7ca4347cbdd48b139208ac5f1127506e59c16410587ab782821f5' 
  AND token = 'D0jujpP9EYPvAe9qRkhOlLqbCVElgaQwHcPH0QZiuzs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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