SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '685639a8d300706a13f6741627976e2a3cac6c9ccc9a5fc1b0237ab2b93cd15a' 
  AND token = 'htWucNsdMXBVtnClnK2Kbm4JDyl/mJSmkL5PXvNSFmE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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