SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6ef02d66db94829ce8bba1055de15cb699bdda8bd1db94e612401316231cef71' 
  AND token = '+ExiUODjP4aHpWas9WMTy4txvjjnFmprAMOgOA9WCW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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