SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '202681e41fe10eff0559e04087f5d1e3fa526c8d94c20a7d93bc3729b07d8f26' 
  AND token = 'LgpuM32dmc1nZPMgUjiRzhBjt7V4dTBSbpszP74u+HA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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