SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2439b9d57db07bb394c9681809b7d652fd60f9815429e0514459dfd682d434ba' 
  AND token = 'RImYexTRsa4LO8F8I+bSXOsfqyEGCnEzn3CH8qz2+wE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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