SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39da49d026528b6c84a1e62fdd9b7aa037bd3bb76f6132a2892535a5ad74f941' 
  AND token = 'QBC173RNhHDlgDwZQug00JU4HwI9AqX8AkERJG23GiA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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