SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7bffe56f32dc51882fcc3d9313d40e9294ade7a766b21d50c1dcfe7b51dc271' 
  AND token = 'gWeH+I1iHEYiTnry5f10ySeTs9Z8reOZqricahiNMNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}