SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad747dec9f88ff72a8c804d042366493a60694869c75ab89f7d76032639e85d0' 
  AND token = 'ufpT+MLHHQosaYRGh7YSIxDBo+1RsUX77kt55GLunDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}