SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39a388d78e1a5b7d5f27d344ceccca635c855e8362f3ae770bdb978e0742258c' 
  AND token = 'twJb2XyM4opd5DZtBuLV8l5HBVzbuWg34bfI5msYmvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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