SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd39692be0486f4d89097b1f0c53a31087a91d873037f9be7872cb7f1c13692b6' 
  AND token = '/UJJ+o7usQD/rhuTyyCIbUz0MRYJ6jIIKO+QTHt+Tkg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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