SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '556295d1d3ddfaf593d6a4759685d35958e1eb31eab456cb1d00ef0efa14220c' 
  AND token = 'Wy6MYoJFF1AxY6UIi0u4XLdlLgJz/AzaeSMXVXa+AiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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