SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b16169469d8348aaa301a04c519b80123ec2dd5dcd59a8259891903e25274dc4' 
  AND token = 'j8Se1qefnygEeqPQdNbaUeo5QdXoujtfK6Lr6AGeEA4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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