SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a0e7f206046bc1684c24a6c503bed3e5ad5d112d2ddbe765d743ae4eab5b652' 
  AND token = 'xaW08TQQTS2U2A0fxqMQGKAFsIWEpAQHbSjUSpVH9Lw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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