SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ead35743a513e7f33c202a0594f6804779400f7d6a30dac648587f6848516a21' 
  AND token = '5R7DdNa+0I0aB8gVvzNdqx/JcVuTOHVmrQa4LvlguKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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