SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6268f56b4a03c13e2b4b74add9a8cce547d10fa6bbae219428e1158d21efa94c' 
  AND token = 'q3gFmmzxrIS5S/lNCAcSdHibx8WUk7/99xvUm3sbQfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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