SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e3e95356d6e73f5bde74eb60a916e6855fbb95b068abf19d82ae498b6af2c3c' 
  AND token = 'PupbCP+5NyKlyi8o0lkiRtKA/AF7oF4i9xMmxk9BZno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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