SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7609a250e053211bd7f62458821731de2be7f2bdc5facee92b626ebccb4cda2' 
  AND token = 'yBzJjGygpPvyOLPirYErgZXW6QYt2hl9fWB5R8DlHDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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