SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db8c57f04d28546766e6616c52641b236d73226ad328db0bd62128a3b6fee515' 
  AND token = 'gWKWABj9KgUl9mzB7pSUYWmf5RNoFDNkFcxpVbWLzgU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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