SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f67bd16ad9eb161772df95b851548424cbeed37cc981c487755e434bba3471f6' 
  AND token = 'onFI6b8mLJK72GR+ZkfpLcH4K84ZzjXrQO7CQHBvMMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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