SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4270f652388c09d76148277d8ed77605555ac363c88277008b8510088577d0b' 
  AND token = 'qhJ2NQS7GSyPDOpef2wmMmApOTYg2CWazTGWsuj0X9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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