SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b0ac214cc5c9879149228c5a58934614917a005a2f28c11a182d582b3667319' 
  AND token = '7RT6TjStPJZTJctgWHexQ0GYL5P6D1HBj+QMHOBMB6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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