SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6a0a2a2da57171c0a1f29763fb8dbb3a7f7208125b5d23be5dd2f132c0d55b62' 
  AND token = 'tuDB5f3Cx07BCdm2PBHneTOWex2sjGiAZtN+0GZkteI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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