SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b082baa63b85ef1d989990d25ed21e921625243d9beaea6de3122c37ce91d09b' 
  AND token = 'mP/bY6OEpLlzj0Szo/R3qUfY/dJW0Sbg6qaWf+Yavag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}