SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c00381d8a6a472948428dfe4539a91989b1da8b1cb40d479fd5964c353b857f7' 
  AND token = '+aJOaC+QVydBnGh2eqOiv+sguj7P5fs7Zq+4NEbiXKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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