SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27f7f9962e7902760a772ef4e6a39c958789ad6f546eddedcc0916aebbdac2b6' 
  AND token = '/bIaRqzjwVU/wBwGYgRZZ5eLx6H7RtYHPo7CZwI/e3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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