SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '55e1a9f0c8a7e3c6190a51a2edbcea158e016537dc38057b3dcfd1fd9126dbde' 
  AND token = '8txpSDTesa4CUVQrWWKpAABWqR1frgS44RGM78LV++E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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