SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2a6d15e20ac0d96821af56f040e206c071f12e9f4806a4849e472e6ab5a8485' 
  AND token = 'BA1XOeJz2+RRYQTm7EZ5r20i8Po6zP2h7GP0kLZsl88=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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