SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f029d94f55e1d41a421a00bf176f509e71f54839d3aa095d791bbeccd8b08bc' 
  AND token = 'GjO6MgcDSy/xD9cdtVH8ngn48t3j6eoBdzDayl+viC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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