SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b38866652dfc145d1d6fd903c2f432c8d5ea4467d7b560da802b4d73821a3ca7' 
  AND token = '2Y5brbsEW9YBv6DZEt9gXpHY/ID4BfL3tgCf8qWhE2g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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