SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '277a4ee40c97384e5adcc614cbaa37aef3b37ef05b69daa9d34beb393060ba44' 
  AND token = 'n7u8EgjXe2V/UdWlsKHtucDi0B22pRA+8UxpsSGPHkg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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