SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbcd711ef748adc0a337933fa7151b3e34f7558402cdca8c156dc9b9ed89df76' 
  AND token = 'Nt6I4+hGTuOTpKzgKsPDg0rwkvoG5t9Y0ZMXaHC4pYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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