SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a76e98342f3d3fc165bf7821717b4f7e8d3bdd24958e436eeaf33f31534e2df' 
  AND token = 'Qn9LXCRwZwNcQu33QXgo/vW7zjjR5e9uov7ZHTLRsR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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