SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e44f57fe7626963b65b239b9aade3dd137735f9a0d8923c501b3a238aa8b45e' 
  AND token = 'v6MtLDKXQrDiNOrVqwbRLxjnHS73JiGytk3W/MYu+lU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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