SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ca070cf460eb757f1b4bacb572c77a0c1041a77b3901f08b5e363d008b83790' 
  AND token = 'd3B3nLZnI5AQdvefC65KoeE4+pyYQWoPt+LmVQe7i5E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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