SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '280f103981d9507a5f7013b7f0c14f376f0eb660b0814873ba23fcf5eab614b9' 
  AND token = 'dAygQI94cQu4+J0QqedCoBqj5K3i+jVZU9clNxSirK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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