SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7749993a3e659bb802a9894b77e156dddb8d30a5b025af68b02b1049db25fe8' 
  AND token = '8TQVrKKHnbvfVL1TjBgLGV+STc6lyv86HRTarSL4qFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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