SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1d16870232bf19e4bce92a107589771566418254d868d546428ddc6d71b6fbb' 
  AND token = 'f/2QDpVN+YyPq2L+SsgaveZFteh5X9miVJqyOqnb4eY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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