SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5269e0bf47a5004662a5564acad53d96df5ba6b9bf68b2e852b2acc5e68135f0' 
  AND token = 'AutuEtJ6EMJyUvbnZVME/2XzTxUMDPTXeGgpAAQqLqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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