SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f3f222fb763609140d370e9d7c80ecc93e7d74420a5975d82ca30ae4279fa8c' 
  AND token = 'fGsx5kY/Ra5oeBSQloJ0YVFVyoMzGBFv6vq5HIrBo6A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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