SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56601783ae6faca28882df2f14b331f886a1e86296343be12c5ddbe89b5f27f4' 
  AND token = '4uWbZ+DXMv1aU0rtwK4WkjNhpxiYTihH/M8fGCgpbQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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