SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0194be7d7c5b638ec46b738dd450a45ebcd6f8f3cd9866d970d31809c608bf47' 
  AND token = 'mQGSZt1+PFjZBCmHESrriKMCYqRhiHMzM3P/u5qa9Co=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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