SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4e40868680416dd7e0ce258581065f57083bebe31d1482a05c07968cde4add03' 
  AND token = 'Ea8RflW523PJqFnZSzTobsyVBkgFvFs59VeZ5CfjgyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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