SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a3759f88187236a097f1e5e23c6547f3679987551d1ef5917fda675e4318102' 
  AND token = '2P2qE/DaONz7w1lbn7K9w+FNG3BLSxlTk18XPDW6S/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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