SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2e8b112ffc3c25eb525c13990c9f010cb140e580ccdbd3f18a98e44eb23502e' 
  AND token = 'fCwvNuY5EzhoTBOiIlNtMVqTO5gLhatSOuUBRhWL8+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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