SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae182009efe50b706182a1996d489d976f7a449e73df4bff74462ead9de0ed32' 
  AND token = '3s3lRrm9YSCKUvXF1gj3RP1+DwNm+L/GPUEqIGvFuuc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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